1558 A MANUAL OF ANATOMY 



free extremities, like those of the inner cells, are each provided with 

 a tuft of short, hair-like filaments, and their deep, nucleated ends 

 are related to the terminal arborizations of nerve-fibres. 



The cells of Deiters, which are sustentacular, are situated between 

 the rows of outer hair-cells. Each cell is nucleated and contains a 

 slender filament, known as the sustentacular filament or phalangeal 

 process. This filainent is attached by its base to the basilar mem- 

 brane, and it is prolonged into the tapering upper end of the cell. 

 It terminates in an expansion, which forms a phalanx of the lamina 

 reticularis, to be presently described. 



The cells of Hensen are disposed as a continuous layer, external 

 to, and in continuation of, the lamina reticularis. 



External to the cells of Hensen there are the columnar cells of 

 Claudius. 



The lamina reticularis extends between the heads of the rods of 

 Corti and the cells of Hensen. It consists of phalanges, which are 

 arranged in two (or more) rows — inner and outer. The phalanges 

 of the inner row are formed by the phalangeal processes of the 



SASII-A.(\ MEMBRANE 



Fig. 654. — A Pair of Rods of Corti, from the Rabbit's Cochlea^ 

 Side View (highly magnified) (SchAfer in Quain's 'Anatomy '). 



heads of the outer rods of Corti. The phalanges of the outer row (or 

 rows) are formed by the phalangeal processes of the cells of Deiters. 

 Between the phalanges there are openings through which the outer 

 ends of the outer hair-cells, with their crescentic tufts of hair-like 

 filaments, project. 



The membrana tectoria, or membrane of Corti, which is elastic, 

 is the most superficial structure in connection with the organ of 

 Corti. It extends from the limbus laminae spiralis near, and 

 external to, the attachment of the membrane of Reissner, to the 

 region of the outer hair-cells. It covers (i) the limbus laminae 

 spiralis; (2) the labium vestibulare, and the auditory teeth; (3) the 

 sulcus laminae spiralis; (4) the inner hair-cells; (5) the inner and 

 outer rods of Corti; (6) the cells of Deiters; and (7) the lamina 

 reticularis. 



Auditory Nerve. — The auditory nerve, within the meatus audi- 

 torius internus, breaks up into two divisions — • vestibular and 

 cochlear. 



The vestibular nerve, as it traverses the meatus auditorius in- 

 ternus, presents a gangliform enlargement, called the ganglion of 

 Scarpa, and it divides into three branches. These enter the vesti- 

 bule through the foramina in the superior vestibular area of the 



